Simplified Carrier-Based Space Vector Modulation Scheme for the Modular Multilevel Converter

To improve the dc voltage utilization rate, this paper proposes a simplified carrier-based space vector modulation (SVM) scheme for the modular multilevel converter (MMC). Firstly, by considering each arm as a whole, only eight space vectors are evaluated in each control period. As a result, the vector selection and dwell time calculation process can be simplified. Then, by flexible selection of extra zero vectors in the MMC, the common-mode voltage (CMV) can be suppressed. Finally, phase-shifted carriers are applied to generate multilevel output voltage waveforms. Experimental results show that the proposed SVM scheme can be achieved with suppressed CMV under different modulation indexes, even in overmodulation conditions.